General Electric (Netherlands)

A significant fraction of the long gamma-ray bursts (LGRBs) in the Swift sample have a plateau phase showing evidence of ongoing energy injection. We suggest that many short gammaray bursts (SGRBs) detected by the Swift satellite also show evidence of energy injection. Explaining this observation within the typical SGRB progenitor model is challenging as late time accretion, often used to explain plateaus in LGRBs, is likely to be absent from the SGRB population. Alternatively, it is predicted that the remnant of neutron star-neutron star mergers may not collapse immediately to a black hole (or even collapse at all), forming instead an unstable millisecond pulsar (magnetar) which powers a plateau phase in the X-ray light curve.

ABSTRACT We present ground-based optical photometric monitoring data for NGC 5548, part of an extended multiwavelength reverberation mapping campaign. The light curves have nearly daily cadence from 2014 January to July in nine filters ( BVRI and ugriz ). Combined with ultraviolet data from the Hubble Space Telescope and Swift , we confirm significant time delays between the continuum bands as a function of wavelength, extending the wavelength coverage from 1158 Å to the z band (~9160 Å). We find that the lags at wavelengths longer than the V band are equal to or greater than the lags of high-ionization-state emission lines (such as He ii <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>λ</mml:mi> <mml:mn>1640</mml:mn> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>λ</mml:mi> <mml:mn>4686</mml:mn> </mml:math> ), suggesting that the continuum-emitting source is of a physical size comparable to the inner broad-line region (BLR). The trend of lag with wavelength is broadly consistent with the prediction for continuum reprocessing by an accretion disk with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>τ</mml:mi> <mml:mo>∝</mml:mo> <mml:msup> <mml:mrow> <mml:mi>λ</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>4</mml:mn> <mml:mrow> <mml:mo stretchy="true">/</mml:mo> </mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> </mml:msup> </mml:math> . However, the lags also imply a disk radius that is 3 times larger than the prediction from standard thin-disk theory, assuming that the bolometric luminosity is 10% of the Eddington luminosity ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>L</mml:mi> <mml:mo>=</mml:mo> <mml:mn>0.1</mml:mn> <mml:msub> <mml:mrow> <mml:mi>L</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">Edd</mml:mi> </mml:mrow> </mml:msub> </mml:math> ). Using optical spectra from the Large Binocular Telescope, we estimate the bias of the interband continuum lags due to BLR emission observed in the filters. We find that the bias for filters with high levels of BLR contamination (~20%) can be important for the shortest continuum lags and likely has a significant impact on the u and U bands owing to Balmer continuum emission.

In this paper, a new theoretical model is presented for the sublimation of graphite at hypersonic flight speeds. The aerothermochemical interactions between dissociated air and graphite are treated by means of a nine-component model, including O, O2, N, N2, CO, CO2, C, C3, and CN. The mass-transfer rate, the heat-transfer rate, and the skin-friction coefficient are determined numerically and are then correlated by means of algebraic equations as a function of stagnation pressure, stagnation enthalpy, and wall temperature in the high-Reynoldsnumber stagnation-point flow regime.

Summary Plant pathogens employ effector proteins to manipulate their hosts. Fusarium oxysporum f. sp. lycopersici ( Fol ), the causal agent of tomato wilt disease, produces effector protein Avr2. Besides being a virulence factor, Avr2 triggers immunity in I‐2 carrying tomato ( Solanum lycopersicum) . Fol strains that evade I‐2 recognition carry point mutations in Avr2 (e.g. Avr2 R45H ), but retain full virulence. Here we investigate the virulence function of Avr2 and determine its crystal structure. Transgenic tomato and Arabidopsis expressing either wild‐type ΔspAvr2 (deleted signal‐peptide) or the ΔspAvr2 R45H variant become hypersusceptible to fungal, and even bacterial infections, suggesting that Avr2 targets a conserved defense mechanism. Indeed, Avr2 transgenic plants are attenuated in immunity‐related readouts, including flg22‐induced growth inhibition, ROS production and callose deposition. The crystal structure of Avr2 reveals that the protein shares intriguing structural similarity to ToxA from the wheat pathogen Pyrenophora tritici‐repentis and to TRAF proteins. The I‐2 resistance‐breaking Avr2 V41M , Avr2 R45H and Avr2 R46P variants cluster on a surface‐presented loop. Structure‐guided mutagenesis enabled uncoupling of virulence from I‐2‐mediated recognition. We conclude that I‐2‐mediated recognition is not based on monitoring Avr2 virulence activity, which includes suppression of immune responses via an evolutionarily conserved effector target, but by recognition of a distinct epitope.

DIFFERENTIAL relaying is the commonly accepted means of protecting large power transformers, a-c generators, and station bus systems against internal faults. <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> The methods and circuits employed in various instances, while differing in detail, are all fundamentally the same in basic principle. Briefly speaking, this principle consists in continuously comparing in each phase the current entering the protected equipment with that leaving. As illustrated in the generalized single-line diagram figure 1, the comparison is made by means of current transformers of suitable ratios placed in all the power circuits connecting with the protected equipment. If current transformation takes place within the equipment as in the case of a power transformer, the ratios of the current transformers placed in the various circuits are chosen to have relative values corresponding to the transformation ratios so that the current transformer secondary currents may be compared on a 1:1 basis. The secondary windings of all the current transformers in each phase are connected in parallel with each other to a special kind of current relay usually called a “differential” relay. The current transformers are all connected in the same polarity with respect to the direction of the protected zone so that currents entering and leaving the protected zone will be represented in the secondary circuit by currents of opposite polarities. Normally, with sound equipment these positive and negative components will be equal, except for negligible exciting currents, and their algebraic sum which by the connection is applied to the relay coil will be essentially zero. When a fault occurs within the protected zone, however, the balance is upset and a difference current proportional to the fault current flows in the coil of the relay, causing it to operate and trip circuit breakers in all the connecting circuits, removing the faulted equipment from service.

Graphite thermochemical response tested in simulated environment for use as thermal shield for hypersonic reentry vehicles

UNLABELLED: Antenatal care (ANC) represents a delivery platform for a broad range of health services; however, these opportunities are insufficiently utilised. This review explores key barriers and enablers for successful integration of health s"ervices with ANC in different contexts. Data from peer-reviewed and grey literature were organised using the SURE checklist. We identified 46 reports focusing on integration of HIV, tuberculosis, malaria, syphilis or nutrition services with ANC from Asia, Africa and the Pacific. Perspectives of service users and providers, social and political factors, and health system characteristics (such as resource availability and organisational structures) affected ease of integration. TWEETABLE ABSTRACT: Health system factors, context and stakeholders must be considered for integrated antenatal care services.

BACKGROUND: Generalist predators may vary their diet and use of habitat according to both internal state (e.g. breeding stage) and external (e.g. weather) factors. Lesser black-backed gulls Larus fuscus (Linnaeus 1758) are dietary generalists, foraging in both terrestrial and marine habitats during breeding. We investigate what affects the gulls' propensity to forage at sea or on land. We assess the importance of terrestrial foraging to gulls in the Baltic Sea (sub. sp. L. f. fuscus), looking especially at their use of agricultural fields. RESULTS: Through the GPS tracking of 19 individuals across 3 years we tracked 1038 foraging trips and found that 21.2 % of foraging trips were predominantly terrestrial, 9.0 % were a mix of terrestrial and marine, and 68.5 % were exclusively marine. Terrestrial trips were (1) more frequent when departing around sunrise, whereas marine trips occurred throughout the day. Additionally, trips with mostly land-based foraging decreased as the breeding season progressed, suggesting dietary switching coincident with the onset of chick provisioning. (2) During cloudy and cold conditions terrestrial foraging trips were more likely. (3) We found no differences between sexes in their land-based foraging strategy. (4) Gull individuals showed great variation in foraging strategy. Using observations of agricultural fields, carried out for one year, we found that (5) gulls preferentially foraged on fields with short vegetation, and there was a positive association with occurrence of waders and other species of gulls. (6) The availability and use of these preferred fields decreased through the breeding period. CONCLUSIONS: This study found high prevalence of terrestrial foraging during early breeding as well as support for dietary switching early in the breeding season. The overall tendency for marine or terrestrial foraging was consistent within individuals, with gull identity accounting for much of the variation observed in foraging trips. Our results suggest that anthropogenic terrestrial food sources may play a role in the low breeding success of these gulls through either variation in quantity and/or quality. Finally, our study demonstrates the potential of combining data from GPS-tracking of individual animals with the 'ground-truthing' of habitat visited to elucidate the otherwise nebulous behavior of a generalist predator.

BACKGROUND: Multiple pathway databases are available that describe the human metabolic network and have proven their usefulness in many applications, ranging from the analysis and interpretation of high-throughput data to their use as a reference repository. However, so far the various human metabolic networks described by these databases have not been systematically compared and contrasted, nor has the extent to which they differ been quantified. For a researcher using these databases for particular analyses of human metabolism, it is crucial to know the extent of the differences in content and their underlying causes. Moreover, the outcomes of such a comparison are important for ongoing integration efforts. RESULTS: We compared the genes, EC numbers and reactions of five frequently used human metabolic pathway databases. The overlap is surprisingly low, especially on reaction level, where the databases agree on 3% of the 6968 reactions they have combined. Even for the well-established tricarboxylic acid cycle the databases agree on only 5 out of the 30 reactions in total. We identified the main causes for the lack of overlap. Importantly, the databases are partly complementary. Other explanations include the number of steps a conversion is described in and the number of possible alternative substrates listed. Missing metabolite identifiers and ambiguous names for metabolites also affect the comparison. CONCLUSIONS: Our results show that each of the five networks compared provides us with a valuable piece of the puzzle of the complete reconstruction of the human metabolic network. To enable integration of the networks, next to a need for standardizing the metabolite names and identifiers, the conceptual differences between the databases should be resolved. Considerable manual intervention is required to reach the ultimate goal of a unified and biologically accurate model for studying the systems biology of human metabolism. Our comparison provides a stepping stone for such an endeavor.

A theoretical model for the transport of electrons in a wet vapor has been formulated. The medium is considered to consist of electrons, neutral gas atoms, positively charged atomic ions, and charged vapor droplets. The degree of ionization of the gas atoms is assumed to be given by Saha's Law evaluated at the electron temperature, whereas the degree of charging of the vapor droplets is obtained by equating the random electron current in the gas to the thermionic emission current of the vapor droplet at its internal temperature. The electron temperature is determined by equating the Joule heating rate of the electrons to their rate of energy loss due to elastic electron-atom, electron-ion, and electron-droplet collisions and inelastic electron-droplet collisions. The droplet internal temperature is determined by equating the rate of droplet heating due to electron bombardment to the rate of cooling due to atom and ion bombardment. The preceding theory is applied to MHD generator considerations for which the predominate effect of the droplets is found to be the absorption of free electrons from the system. The depression of electron density is found to be most severe at high-percent moisture and for small droplets. IVrONEQUILIBRIUM ionization, as it shall be referred to J- ^ in this paper, is the production of a highly-ionized gas at low gas temperatures as a result of applied and/or induced electric fields in the gas, which serve to heat the electrons. These energetic electrons subsequently ionize the gas to a degree commensurable with their energy rather than that of the cooler gas. This phenomenon has been a long-observed fact in gaseous discharges1' 2 and has recently been considered as a means of producing high electrical conductivities in an MHD generator at gas temperatures compatible with present materials technology.3' 4 In Ref. 4, nonequilibrium ionization, as it applies to MHD generators utilizing noble gases seeded with low concentrations of alkali metal vapors as working fluids, was extensively analyzed. An equation for the electron temperature relative to that of the other species in the gas was obtained by equating the rate at which energy is gained by the electrons in an electromagnetic field, j • (E + u X B) (where j is the electron current, E is the electric field, u is the gas-flow velocity, and B is the magnetic field), to the rate at which energy is given up by the electrons to other species in the gas due to collisions. This energy balance results in the equation

Plant pathogens use effector proteins to promote host colonisation. The mode of action of effectors from root-invading pathogens, such as Fusarium oxysporum (Fo), is poorly understood. Here, we investigated whether Fo effectors suppress pattern-triggered immunity (PTI), and whether they enter host cells during infection. Eight candidate effectors of an Arabidopsis-infecting Fo strain were expressed with and without signal peptide for secretion in Nicotiana benthamiana and their effect on flg22-triggered and chitin-triggered reactive oxidative species (ROS) burst was monitored. To detect uptake, effector biotinylation by an intracellular Arabidopsis-produced biotin ligase was examined following root infection. Four effectors suppressed PTI signalling; two acted intracellularly and two apoplastically. Heterologous expression of a PTI-suppressing effector in Arabidopsis enhanced bacterial susceptibility. Consistent with an intracellular activity, host cell uptake of five effectors, but not of the apoplastically acting ones, was detected in Fo-infected Arabidopsis roots. Multiple Fo effectors targeted PTI signalling, uncovering a surprising overlap in infection strategies between foliar and root pathogens. Extracellular targeting of flg22 signalling by a microbial effector provides a new mechanism on how plant pathogens manipulate their host. Effector translocation appears independent of protein size, charge, presence of conserved motifs or the promoter driving its expression.

Abstract Humans perceive and spontaneously move to one or several levels of periodic pulses (a meter, for short) when listening to musical rhythm, even when the sensory input does not provide prominent periodic cues to their temporal location. Here, we review a multi-levelled framework to understanding how external rhythmic inputs are mapped onto internally represented metric pulses. This mapping is studied using an approach to quantify and directly compare representations of metric pulses in signals corresponding to sensory inputs, neural activity and behaviour (typically body movement). Based on this approach, recent empirical evidence can be drawn together into a conceptual framework that unpacks the phenomenon of meter into four levels. Each level highlights specific functional processes that critically enable and shape the mapping from sensory input to internal meter. We discuss the nature, constraints and neural substrates of these processes, starting with fundamental mechanisms investigated in macaque monkeys that enable basic forms of mapping between simple rhythmic stimuli and internally represented metric pulse. We propose that human evolution has gradually built a robust and flexible system upon these fundamental processes, allowing more complex levels of mapping to emerge in musical behaviours. This approach opens promising avenues to understand the many facets of rhythmic behaviours across individuals and species. This article is part of the theme issue ‘Synchrony and rhythm interaction: from the brain to behavioural ecology’.

Anthocyanins contribute to the appearance of fruit by conferring to them a red, blue or purple colour. In a food context, they have also been suggested to promote consumer health. In purple tomato tissues, such as hypocotyls, stems and purple fruits, various anthocyanins accumulate. These molecules have characteristic patterns of modification, including hydroxylations, methylations, glycosylations and acylations. The genetic basis for many of these modifications has not been fully elucidated, and nor has their role in the functioning of anthocyanins. In this paper, AnthOMT, an O-methyltransferase (OMT) mediating the methylation of anthocyanins, has been identified and functionally characterized using a combined metabolomics and transcriptomics approach. Gene candidates were selected from the draft tomato genome, and their expression was subsequently monitored in a tomato seedling system comprising three tissues and involving several time points. In addition, we also followed gene expression in wild-type red and purple transgenic tomato fruits expressing Rosea1 and Delila transcription factors. Of the 57 candidates identified, only a single OMT gene showed patterns strongly correlating with both accumulation of anthocyanins and expression of anthocyanin biosynthesis genes. This candidate (AnthOMT) was compared to a closely related caffeoyl CoA OMT by recombinant expression in Escherichia coli, and then tested for substrate specificity. AnthOMT showed a strong affinity for glycosylated anthocyanins, while other flavonoid glycosides and aglycones were much less preferred. Gene silencing experiments with AnthOMT resulted in reduced levels of the predominant methylated anthocyanins. This confirms the role of this enzyme in the diversification of tomato anthocyanins.

The optical and electronic properties of novel, alternating quinoxaline/oligothiophene donor–acceptor copolymers show an unexpected independence of absorption and photoluminescence, as well as of the HOMO/LUMO energy levels, on the length of the oligothiophene segments in the copolymer main chain.

Very faint X-ray binaries (VFXBs), defined as having peak luminosities L X of 10 34 -10 36 erg s -1 , have been uncovered in significant numbers, but remain poorly understood. We analyse three published outburst light curves of two transient VFXBs using the exponential and linear decay formalism of King & Ritter. The decay time-scales and brink luminosities suggest orbital periods of order 1 h. We review various estimates of VFXB properties, and compare these with suggested explanations of the nature of VFXBs. We suggest that:

Abstract Two series of novel random polyfluorene copolymers containing quinoxaline units were prepared by stressing the coupling according to Yamamoto. The first series contains 2,3‐ bis ‐(4′‐ tert ‐butyl‐biphenyl‐4‐yl)benzo[ g ]quinoxaline and the second series 2,3‐ bis ‐(4′‐ tert ‐butyl‐biphenyl‐4‐yl)quinoxaline as energy accepting unit. The copolymers were identified by gel permeation chromatography, infrared spectroscopy, and nuclear magnetic resonance spectroscopy. Thermal properties were analyzed by thermal gravimetric analysis and differential scanning calorimetry revealing amorphous copolymers that are stable up to 430 °C. The morphology was investigated using atomic force microscopy. The optical properties in solutions and thin films were analyzed. Furthermore, the thin film electro‐optical properties were determined in monolayer polymer light‐emitting devices. Single layer devices were built with efficiencies ranging from 0.15 to 2.0 cd/A. For the random copolymers with 5 mol % benzo[ g ]quinoxazoline in the polyfluorene backbone some threefold efficiency enhancement from 1.1 to 3.0 cd/A was achieved by utilizing an ultra thin interlayer of poly(9,9‐di‐ n ‐octylfluorene‐2,7‐diyl)‐ alt ‐[1,4‐phenylene‐(4‐ sec ‐butylphenylimino)‐1,4‐phenylene] between PEDOT:PSS and the emissive random copolymer layer. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4773–4785, 2007

We present the first vertically resolved hydrodynamic simulations of a laterally propagating, deflagrating flame in the thin helium ocean of a rotating accreting neutron star. We use a new hydrodynamics solver tailored to deal with the large discrepancy in horizontal and vertical length-scales typical of neutron star oceans, and which filters out sound waves that would otherwise limit our time steps. We find that the flame moves horizontally with velocities of the order of 10 5 cm s -1 , crossing the ocean in a few seconds, broadly consistent with the rise times of Type I X-ray bursts. We address the open question of what drives flame propagation, and find that heat is transported from burning to unburnt fuel by a combination of top-to-bottom conduction and mixing driven by a baroclinic instability. The speed of the flame propagation is therefore a sensitive function of the ocean conductivity and spin: we explore this dependence for an astrophysically relevant range of parameters and find that in general flame propagation is faster for slower rotation and higher conductivity.

This paper presents experimental observations concerning the formation of diamondshaped surface ablation patterns. These patterns have developed on several types of ablation materials (melting, subliming, and char forming) under diverse flow conditions. The pattern angle is shown to correlate with the local Mach angle for all classes of materials. A ratio of the pattern wavelength to the boundary-layer thickness appears to be insensitive to the dimensionless blowing rate or Mach number. The frequent appearance of longitudinal grooves upstream of the diamond patterns suggests a relation between longitudinal vorticity and pattern development. This study emphasizes the surface pattern phenomena on char forming materials.

POWER TRANSFORMERS usually are protected against damage due to internal faults by percentage differential relays, which compare currents on opposite sides of the transformer. However, when a transformer is energized, there is often an inrush of magnetizing current, which flows in only one winding of the transformer, producing a differential current which tends to operate conventional percentage differential relays. Special means, therefore, are necessary to prevent transformer relays from operating falsely on magnetizing inrush currents.

Aql X-1 is a prolific transient neutron star low-mass X-ray binary that exhibits an accretion outburst approximately once every year. Whether the thermal X-rays detected in intervening quiescent episodes are the result of cooling of the neutron star or due to continued lowlevel accretion remains unclear. In this work, we use Swift data obtained after the long and bright 2011 and 2013 outbursts, as well as the short and faint 2015 outburst, to investigate the hypothesis that cooling of the accretion-heated neutron star crust dominates the quiescent thermal emission in Aql X-1. We demonstrate that the X-ray light curves and measured neutron star surface temperatures are consistent with the expectations of the crust cooling paradigm. By using a thermal evolution code, we find that 1.2-3.2 MeV nucleon -1 of shallow heat release describes the observational data well, depending on the assumed mass-accretion rate and temperature of the stellar core. We find no evidence for varying strengths of this shallow heating after different outbursts, but this could be due to limitations of the data. We argue that monitoring Aql X-1 for up to 1 yr after future outbursts can be a powerful tool to break model degeneracies and solve open questions about the magnitude, depth, and origin of shallow heating in neutron star crusts.